Incubator with air curtain

ABSTRACT

An incubator for cell and tissue culture under controlled atmospheric conditions has a primary air flow control device that forms a primary, preferably laminar flow, air veil across an opening that allows access to the cells or tissue cultures disposed within the incubator. Preferably, most if not all of the air in the primary (laminar flow) air veil is recirculated, and a secondary air flow control device is used that forms a secondary, preferably laminar flow, air veil between the primary (laminar flow) air veil and a user of the incubator.

This application is a continuation application of allowed U.S.application with the Ser. No. 17/357,131, filed Jun. 24, 2021, whichclaims priority to U.S. Pat. No. 11,072,773, filed Nov. 24, 2020, whichclaims priority to U.S. Pat. No. 10,900,010, filed Sep. 3, 2020, whichclaims priority to U.S. provisional application with the Ser. No.62/895,587, filed Sep. 4, 2019, all of which are incorporated byreference herein.

FIELD OF THE INVENTION

The present disclosure is directed to devices, systems, and methods ofincubators with controlled atmosphere, particularly as it relates tocell and tissue culture incubators with low-oxygen atmosphere.

BACKGROUND OF THE INVENTION

The background description includes information that may be useful inunderstanding the present disclosure. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

All publications and patent applications herein are incorporated byreference to the same extent as if each individual publication or patentapplication were specifically and individually indicated to beincorporated by reference. Where a definition or use of a term in anincorporated reference is inconsistent or contrary to the definition ofthat term provided herein, the definition of that term provided hereinapplies and the definition of that term in the reference does not apply.

As is well known, the oxygen in the atmosphere is approximately 21 vol %at sea level, and many cell and tissue culture experiments are performedwithout specific control of oxygen content in the cell and tissueculture incubator. As a consequence, cells and tissues grown in suchincubators are exposed to oxygen levels that are not representative ofphysiologically normal oxygen levels in vivo. Indeed, it has been arguedthat all or almost all cells in a living multicellular organism exist inenvironments with oxygen levels that are well below atmospheric levelsof oxygen (see e.g., Int J Mol Sci. 2019; 20, 1195;doi:10.3390/ijms20051195). For example, oxygen is typically foundbetween 0.5-7% in the brain, between 1-5% in the eyes, between 4-12% inthe liver, heart, and kidneys, and between 3-5% in the uterus. On thebackdrop of the varying oxygen levels for specific cells and tissues,physiologically appropriate oxygen levels have bene termed ‘Physoxia’(Stem Cell Research & Therapy (2018) 9:148). In addition, it has beenshown that atmospheric oxygen levels in cell and tissue culture severelyaffect various metabolic and developmental processes. For example,‘normoxic’ (i.e., 21% O₂) culture conditions suppress in vitro geneexpression of a variety of genes, cell differentiation, proliferation,and viability of numerous stem cell lines, suppress expression ofregulatory and housekeeping genes of numerous cell lines, and tend toaffect metabolism and metabolic pathways of most cells.

Moreover, the significance of appropriate oxygen levels for specificcells and tissues has also been recognized in numerous studies thatdemonstrated that reproducibility of experiments is jeopardized or evenimpossible where oxygen levels in the cell cultures were not reported orsuitably adjusted (PLOS ONE|https://doi.org/10.1371/journal.pone.0204269Oct. 16, 2018). To help overcome at least some of the difficultiesassociated with appropriate oxygen control, incubators can be suppliedwith gases to adjust oxygen levels within the incubator, and a tri-gasincubator is one common variant of such devices (see e.g., ThermoFischer Scientific, Tri-gas incubators). Here, carbon dioxide andnitrogen are fed at controlled rates into the incubator to maintainrelatively constant gas conditions. Unfortunately, however, such tri-gasincubators are still subject to large oxygen excursions during operationand particularly when the incubator door is opened to add or remove aculture container. In yet another approach, modular incubator chamberscan be used to more tightly control the environmental conditions (seee.g., MIC-101 by Billups-Rothenberg, Inc.). Such incubators offer asimple yet effective manner of atmospheric containment, which can befurther monitored and controlled with a suitable gas mixing system and amodular oxygen monitor that can be placed within the modular incubator.However, such systems are often limited in capacity and need placementwithin an existing incubator for temperature control.

Compounding the above difficulties are normal operations during cellculture that require one or more culture vessels to be removed from anincubator, for example, for visual analysis and cell count, feeding ormedia exchange, and cell harvesting. Indeed, it is not unusual for astandard size incubator to be repeatedly opened and closed multipletimes within only one or two hours. As will be readily appreciated, eachtime an incubator is opened, the controlled atmospheric conditions arelost and must be re-established to ensure proper culture conditions uponclosing the incubator. Unfortunately, even with active airflowcirculation, the time to re-establish proper temperature, humidity, andoxygen content readily exceed 5-10 minutes every time the incubator isopened as is exemplarily depicted in FIG. 1. As a consequence, the cellor tissue cultures in the incubator will experience multiple andsignificant deviations from the set points for the atmosphericconditions. Still further, each opening and closing cycle of anincubator will expose the entire internal volume and culture vessels topotential microbial contamination, which could jeopardize the entirecontents of the incubator.

Thus, even though various cell culture incubators are known in the art,all or almost all of them suffer from various disadvantages. Mostnotably, ordinary use of the incubators will disrupt atmosphericconditions within the incubator, and re-establishment of the appropriateconditions is time consuming. Consequently, cells and tissues in thecurrently known incubators will be exposed to long periods of off-targetconditions, changing conditions during re-establishment of the on-targetconditions, and microbial contamination. Still further, conventionalincubators are subject to incursion of large volumes of air upon openingthe doors, leading to a substantial increase of microbial contamination.Therefore, there is still a need to provide improved incubators thatprovide effective atmospheric and environmental control with reducedexposure to microbial contaminants.

SUMMARY OF THE INVENTION

Incubators with effective atmospheric and environmental control aredisclosed herein that use at least a primary air flow control devicethat directs a primary air veil along or parallel to the opening of theincubator. Most typically, a substantial portion of the air in theprimary air veil is re-circulated and optionally adjusted in temperatureand/or composition to accommodate changes in temperature and/orcomposition.

In one aspect, the inventors contemplate an incubator that has a housingthat at least partially encloses an internal container, wherein theinternal container has an opening. A door is coupled to the housingand/or the internal container and movable between a first positionallowing access to the internal container from an outside position ofthe incubator and a second position preventing access to the internalcontainer from the outside position of the incubator. Moreover, theincubator includes a primary air flow control device that is coupled tothe housing and/or the internal container and that directs a primary airveil along or parallel to a hypothetical plane covering the opening.

In some contemplated aspects, the incubator also includes a secondaryair flow control device that is coupled to the housing and/or theinternal container to direct a secondary air veil substantially parallelto the primary air veil. Moreover, it should be appreciated thatcontemplated incubators will preferably also include a primary and/orsecondary suction fan, wherein the primary suction fan is positioned toreceive air from the primary air veil, and wherein the secondary suctionfan is positioned to receive air from the secondary air veil. Mosttypically, but not necessarily, the primary air veil and/or thesecondary air veil is/are a directional veil or a laminar flow veil.Additionally, it is contemplated that the primary air flow controldevice may also have a movable vane to at least temporarily direct (aportion or all of the) air from the primary air veil into the internalcontainer.

In further contemplated aspects, the door of the incubator is movable ina compound motion that moves the door away and in an upward motion fromthe opening. Moreover, it is contemplated that the housing, the internalcontainer, and the primary air flow control device are positionedrelative to each other such as to form a recirculation space that allowsfor recirculation of air in the primary air veil. Advantageously,recirculation of the air in the primary air veil will recirculate atleast 70%, or at least 8%, or at least 90% of the air in the veil.

Contemplated incubators may further include a filter unit, an absorberunit, a sterilization unit, a temperature control unit, a temperaturesensor, a humidity sensor, an atmospheric pressure sensor, and/or a gassensor, preferably at least partially disposed within the recirculationspace. In addition, the incubator may also comprise a gas inlet throughwhich a gas from an external source is fed to the recirculation space.

Where desired, the incubator includes a control circuit that iselectronically coupled to the door, the primary air flow control device,and the secondary air flow control device. Preferably, the controlcircuit is programmed to operate the primary and/or secondary air flowcontrol device, for example, once the door has started to move from thefirst to the second position. Furthermore, contemplated incubators mayinclude an access control device that is programmed to receive a usercommand and/or validate an authorized user of the incubator, and mayfurther be couple to a membrane filter or pressure swing adsorption unitthat generates a nitrogen rich product that is delivered to theincubator as further described in more detail below.

The incubator may also include one or more trays that are movablycoupled to the internal container and that have (e.g., honeycomb)channels for passage of the primary laminar flow air veil therethroughwhen the tray(s) is/are pulled through the first air veil. In addition,it is also contemplated that the internal container of the incubator iscoupled to the housing via a movable coupling (e.g., rail or telescopingsystem) that allows movement of the internal container out of thehousing.

Therefore, viewed from a different perspective, the inventors alsocontemplate an incubator that comprises a housing that at leastpartially encloses an internal container, wherein the internal containerhas an opening. Such incubator will further include a primary air flowcontrol device that is coupled to the housing and/or the internalcontainer that directs a primary air veil along or substantiallyparallel to a hypothetical plane covering the opening. Most typically,the housing, the internal container, and the primary air flow controldevice are positioned relative to each other to form a recirculationspace that allows for recirculation of air in the primary air veil,wherein the recirculation space at least partially encloses a pluralityof sensors selected from the group consisting of a CO₂ sensor, an O₂sensor, a humidity sensor, an atmospheric pressure sensor, andtemperature sensor, and further at least partially encloses asterilization unit, a high-efficiency particulate air (HEPA) filter, anactivated charcoal filter, and/or a heater.

Where desired, the incubator will also include a secondary air flowcontrol device that is coupled to the housing and/or the internalcontainer and that directs a secondary air veil substantially parallelto the primary air veil. Moreover, it is contemplated that the incubatormay also include a primary and/or secondary suction fan, wherein theprimary suction fan is positioned to receive air from the primary airveil, and wherein the secondary suction fan is positioned to receive airfrom the flow air veil. Preferably, but not necessarily, the secondaryair flow control device is configured to receive ambient air, and thesecondary suction fan expels the secondary air veil to the ambient air.

In further contemplated aspects, the primary air veil and/or thesecondary air veil is/are a directional veil or a laminar flow veil,and/or the primary air flow control device recirculates at least 90% ofall air in the primary air veil through the recirculation space. In someembodiments, the recirculation space at least partially encloses atleast two of the CO₂ sensor, the O₂ sensor, the sterilization unit, thehigh-efficiency particulate air (HEPA) filter, the activated charcoalfilter, and/or the heater. In other embodiments, the recirculation spaceat least partially encloses at least three of the CO₂ sensor, the O₂sensor, the sterilization unit, the high-efficiency particulate air(HEPA) filter, the activated charcoal filter, and/or the heater, whilein further embodiments the recirculation space at least partiallyencloses the CO₂ sensor, the O₂ sensor, the sterilization unit, thehigh-efficiency particulate air (HEPA) filter, the activated charcoalfilter, and the heater. Where desired, the sterilization unit comprisesa UV light source directed towards a titanium dioxide containingsurface.

In still further contemplated aspects, the inventors also contemplate anincubator control unit for an incubator that has a door movable betweena first position allowing access to the internal container from anoutside position of the incubator and a second position preventingaccess to the internal container from the outside position of theincubator, and that has a primary air flow control device. In especiallypreferred aspects, the incubator control unit includes a microprocessorand a memory storing instructions executable on the microprocessor,wherein the instructions cause the control unit to: (a) down-regulatethe primary air flow control device and optionally cause movement of avane coupled to the primary air flow control device upon the door movinginto the second position; (b) up-regulate the primary air flow controldevice and an optional secondary air flow control device upon the doormoving into the first position; and/or (c) cause movement of a vanecoupled to the primary air flow control device when the door is in thefirst position.

As will be readily appreciated, the control unit may be furtherelectronically coupled to a temperature sensor, a gas sensor, anatmospheric pressure sensor, and/or a humidity sensor, and theinstructions may cause the control unit to activate a heater, open a gasvalve to allow entry of a gas into the incubator, and/or activate ahumidifier. Additionally, or alternatively, the instructions may alsocause the control unit to activate the heater, to open the gas valve toallow entry of the gas into the incubator, and/or activate thehumidifier while the door is in the first position. Most typically, thegas sensor is an O₂ sensor and/or a CO₂ sensor.

In some embodiments, the control unit is further electronically coupledto an access control device that is programmed to receive a user commandand/or validate an authorized user of the incubator. Most typically, theinstructions cause the control unit to move the door from the first tothe second position upon receiving the user command and/or validation ofthe authorized user. While not limiting to the inventive subject matter,the user command is a voice command or visual/gesture command.Therefore, in some embodiments the authorized user is validated by facerecognition. Additionally, the control unit may also be electronicallycoupled to a sterilization unit, and the instructions cause the controlunit to activate the sterilization unit.

In yet further contemplated aspects of the inventive subject matter, theinventors contemplate a method of maintaining a controlled atmosphere(e.g., hypoxic atmosphere) in an incubator, where such method willinclude a step of flowing a primary air veil along or parallel to ahypothetical plane covering an opening in an internal container of theincubator while access to the internal container is enabled from anoutside position of the incubator, wherein at least 90% of air in theprimary air veil is recycled through the incubator.

As noted earlier, it is contemplated that at least 90% or 95% of air inthe primary air veil is recycled through the incubator. Moreover,contemplated methods may also include a step of flowing a secondary airveil substantially parallel to the primary air veil. Most typically,less than 10% of the secondary air veil is recycled through theincubator, and/or the primary air veil and/or the secondary air veil isa directional veil or a laminar flow veil. In further suitableembodiments, the primary and/or secondary air veil is formed using aplurality of primary/secondary air flow control devices. Most typically,the secondary air veil flow substantially parallel to the primary airveil, and/or the primary air veil and/or the secondary air veil is/are adirectional veil or a laminar flow veil.

Further suitable methods include a step of using an incubator controlcircuit that controls a gas valve, a heater, and/or a humidifier,wherein the control circuit receives signals from a gas sensor, atemperature sensor, and/or a humidity sensor, wherein the gas sensor,the temperature sensor, and/or the humidity sensor sense a gas, atemperature and/or a humidity in the air that is recycled through theincubator. For example, the atmosphere is controlled such that atemperature excursion, while access to the internal container is enabledfrom the outside position of the incubator, is less than 5° C. Inanother example, the atmosphere is controlled such that a gasconcentration excursion, while access to the internal container isenabled from the outside position of the incubator, is less than 2%(absolute), and in yet another example, the atmosphere is controlledsuch that a humidity excursion, while access to the internal containeris enabled from the outside position of the incubator, is less than 5%(absolute).

Viewed from a different perspective, the inventors also contemplate amethod of re-establishing a controlled atmosphere in an incubator thatincludes a step of allowing access to an internal container of theincubator from an outside position of the incubator through a primaryair veil that extends along or substantially parallel to a hypotheticalplane covering an opening in the internal container, wherein accesschanges the controlled atmosphere. In another step, at least some of theair in the primary air veil is recirculated through a recirculationspace in the incubator while access is allowed, and in a further step atleast one parameter (e.g., O₂ concentration, CO₂ concentration,humidity, and/or temperature) of the controlled atmosphere is measuredin the recirculation space while the primary air veil is re-circulated.Additionally, the at least one parameter can then be adjusted byinjecting a gas into the recirculation space and/or heating the air inthe recirculation space while the primary air veil is re-circulated.

Preferably, but not necessarily, at least 90% of air in the primary airveil is recycled through the incubator, and/or the step of adjusting isperformed while access is allowed. In addition, contemplated methodsalso allow for a step of changing a vane angle at a primary air flowcontrol device that produces the primary air veil to enable mixing ofair in the internal container of the incubator. Most typically, theprimary air veil is a directional veil or a laminar flow veil. In yetfurther aspects of contemplated methods, at least a portion of theprimary air veil may be directed into the internal container. In mostcases, the controlled atmosphere in the incubator is re-establishedwithin equal or less than one minute from a maximum excursion.

In still further aspects, a method of reducing excursion of anenvironmental parameter of a controlled atmosphere in an incubator whileopening access to an internal container of the incubator from an outsideposition of the incubator is contemplated. Such method will include astep of flowing a primary air veil along or parallel to a hypotheticalplane covering an opening in the internal container of the incubatorbefore opening a door to provide access to the internal container of theincubator. Upon establishing the primary air veil, the door is thenmoved in a compound motion that moves the door away and in a lateralmotion from the opening, and upon moving the door, a secondary air veilis flowed substantially parallel to the primary air veil.

For example, at least 90% of the air in the primary air veil may berecirculated within the incubator, and equal or less than 10% of the airin the secondary air veil is re-circulated within the incubator. Inother examples, the flow rate of the primary air veil may be increasedupon or after moving the door, or a portion of the primary air veil maybe directed into the internal container of the incubator. Where desired,the primary air veil is generated by a plurality of primary air flowcontrol devices.

In still further contemplated aspects, the inventors also contemplate amethod of reducing gas (e.g., tri-gas consumption) consumption in acontrolled atmosphere incubator, and such methods will include a step offeeding air, nitrogen, and/or carbon dioxide into a recirculation spacein the incubator, wherein the recirculation space is fluidly coupled toa primary air flow control device. In another step, the primary air flowcontrol device is used to flow a primary air veil along or substantiallyparallel to a hypothetical plane covering an opening in an internalcontainer of the incubator while access to the internal container isenabled from an outside position of the incubator. Most typically, atleast 90% or 95% of air in the primary air veil is recycled through theincubator.

While not limiting the inventive subject matter, it is generallypreferred that the primary air veil is a directional veil or a laminarflow veil, and/or that a secondary air veil is flowed substantiallyparallel to the primary air veil. In some embodiments, the nitrogen isprovided from a membrane filter or pressure swing adsorption unit, andmost typically, the controlled atmosphere is a hypoxic atmosphere.

Moreover, the inventors also contemplate a gas supply system for acontrolled atmosphere incubator that includes an ambient air compressorthat is fluidly coupled to a gas mixing unit via a first conduit, asecond conduit coupling the ambient air compressor to a pressure swingabsorption (PSA) unit or a membrane filtration unit, wherein the PSA ormembrane unit produces a nitrogen rich product. Most typically, thesecond conduit further couples the PSA or membrane unit to the gasmixing unit, and a third conduit couples the gas mixing unit to thecontrolled atmosphere incubator. Where desired, the gas supply systemwill also include a source of compressed CO₂ fluidly coupled to the gasmixing unit via a fourth conduit.

In preferred aspects, the first, the second, the third, and/or the thirdconduit will include a flow control valve and/or a mass flow meter. Mosttypically, the gas supply system will also have an O₂ and a CO₂ sensordownstream of the gas mixing unit. Preferably, the first and/or thesecond conduit will comprise a surge tank, and/or the third conduit isfluidly coupled to a reservoir upstream of the controlled atmosphereincubator. Additionally, it should be appreciated that in gas supplysystems contemplated herein the third conduit is fluidly may be coupledto a second reservoir upstream of a second controlled atmosphereincubator.

In yet further embodiments, the inventors also contemplate an incubatorthat has a housing that at least partially encloses an internalcontainer (typically having a volume of between 10 and 200 L), whereinthe internal container has an opening. A primary air flow control deviceis coupled to the housing and/or internal container and positionedrelative to the internal container to direct a primary air veil along orsubstantially parallel to a hypothetical plane covering the opening, anda secondary air flow control device is coupled to the housing and/orinternal container and positioned relative to the internal container todirect a secondary air veil parallel to the primary air veil.Additionally, a door is coupled to the housing and/or internal containersuch that the entire door is movable away from the hypothetical planeand such that the entire door is moveable in a horizontal or verticaldirection.

In some embodiment, the internal container, and the primary air flowcontrol device are positioned relative to each other to form arecirculation space that allows for recirculation of air in the primaryair veil. Most typically, the recirculation space encloses at leastpartially a plurality of sensors (e.g., CO₂ sensor, O₂ sensor, humiditysensor, atmospheric pressure sensor, and/or temperature sensor), and mayfurther at least partially enclose additional functional components(e.g., sterilization unit, high-efficiency particulate air (HEPA)filter, activated charcoal filter, and/or a heater).

Where desired, the incubator may also include a primary and/or secondarysuction fan, wherein the primary suction fan is positioned to receiveair from the primary air veil, and wherein the secondary suction fan ispositioned to receive air from the flow air veil. In furtherembodiments, the secondary air flow control device may be configured toreceive ambient air and the secondary suction fan expels the secondaryair veil to the ambient air.

Typically, but not necessarily, the primary air veil and/or thesecondary air veil is a directional veil or a laminar flow veil. Inadditional embodiments, the primary air flow control device recirculatesat least 90% of all air in the primary air veil through therecirculation space and/or may further comprise or be coupled to amovable vane that controls the direction of the primary air veil. Instill further embodiments, the primary and/or secondary air veil has anairflow between about 0.3 to 0.6 m/s

Additionally, it is contemplated that the incubator may include acontrol unit having a microprocessor and a memory storing instructionsexecutable on the microprocessor, wherein the instructions cause thecontrol unit to: a) down-regulate the primary air flow control deviceand optionally cause movement of a vane coupled to the primary air flowcontrol device upon the door moving into a closed position; b)up-regulate the primary air flow control device and an optionalsecondary air flow control device upon the door moving into an openposition; and/or c) cause movement of a vane coupled to the primary airflow control device when the door is in the open position. Wheredesired, the control unit may further be electronically coupled to atemperature sensor, a gas sensor, an atmospheric pressure sensor, and/ora humidity sensor, and the instructions may cause the control unit toactivate a heater, open a gas valve to allow entry of a gas into theincubator, and/or activate a humidifier. Moreover, the control unit maybe electronically coupled to an access control device that is programmedto receive a user command (e.g., voice command or user gesture) and/orvalidate an authorized user (e.g., by face recognition) of theincubator, and the instructions cause the control unit to move the doorfrom the closed to the open position upon receiving the user commandand/or validation of the authorized user.

In still further embodiments, the door, when in a closed position, maybe positioned in an area otherwise occupied by the secondary air veil(with the secondary air veil not operating).

Various objects, features, aspects, and advantages will become moreapparent from the following detailed description of preferredembodiments, along with the accompanying drawing in which like numeralsrepresent like components.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 depicts exemplary graphs for recovery of selected environmentalparameters of known incubators.

FIG. 2 depicts an exemplary view of schematic airflow in an incubatorwith closed door according to the inventive subject matter.

FIG. 3 depicts an exemplary view of schematic airflow in an incubatorduring door opening according to the inventive subject matter.

FIG. 4 depicts an exemplary view of schematic airflow in an incubatorwith open door according to the inventive subject matter.

FIG. 5 depicts an exemplary view of schematic airflow in an incubatorwith open door in flush mode according to the inventive subject matter.

FIG. 6 depicts an exemplary view of an internal container andrecirculation space showing selected components.

FIG. 7 depicts an exemplary graph of air flow characteristics as afunction of flow height and exit velocity.

FIG. 8 depicts an exemplary view of simulated airflow usingcomputational fluid dynamics modeling in an incubator with the internalcontainer and recirculation space of FIG. 6 at lower air speed.

FIG. 9 depicts an exemplary view of simulated airflow usingcomputational fluid dynamics modeling in an incubator with the internalcontainer and recirculation space of FIG. 6 at higher air speed.

FIG. 10 depicts an exemplary view of one alternate configuration inwhich the internal container and the recirculation space are notcoextensive.

FIG. 11 depicts an exemplary view of an incubator with closed dooraccording to the inventive subject matter.

FIG. 12 depicts an exemplary view of an incubator with open dooraccording to the inventive subject matter.

FIG. 13 depicts an exemplary detail showing air intakes for the primaryand secondary suction fans.

FIG. 14 depicts an exemplary detail showing primary and secondary airflow control devices.

FIG. 15 depicts an exemplary perspective view of an incubator accordingto the inventive subject matter with cell culture containers.

FIG. 16 an exemplary schematic for a gas supply system according to theinventive subject matter.

FIG. 17 depicts an exemplary schematic for a gas supply system forindependent operation of multiple incubators according to the inventivesubject matter.

DETAILED DESCRIPTION

The inventors have now discovered that cell and tissue cultureincubators can be manufactured and operated in a conceptually simple yeteffective manner that provides superior atmospheric and environmentalcontrol. Indeed, the incubators presented herein have demonstrated aheretofore unobtainable operational stability with respect to controlledatmospheric conditions within the incubator, even when the incubator isopened and a user interacts with content within the incubator. Suchoperational benefits are achieved by use of one or more air veils thatare directed along or substantially parallel to a hypothetical planecovering the opening wherein a significant portion of the air in the airveil is re-circulated. Moreover, the composition, flow rate, and/ortemperature or the air in the air veil can be adjusted in real-time, andwhere desired, a portion of the air veil can be directed into theincubator (e.g., using a movable vane) to replace or supplement air lostform the inside of the incubator.

In contrast, it should be appreciated that contemplated incubators andmethods therefor presented herein are significantly distinct from knownlaminar flow sterile hoods, laminar airflow workstations, or biosafetycabinets where the air within the entire chamber is subject to verticalflow. While such devices will protect the cells or material that iswithin the chamber, such devices are unsuitable for cell and tissueculture as these which devices will fail to maintain operationalparameters within the tight requirements of cell or tissue culture. Mosttypically, air is drawn into these devices, filtered, and then exits thedevice without providing any significant control (e.g., maintenance ofhypoxic conditions for stem cell cultures). Viewed from a differentperspective, air flow in such laminar flow cabinets is a single passflow through.

Therefore, and in a more general aspect of the inventive subject matter,the inventors contemplate an incubator that has a housing that at leastpartially encloses an internal container, wherein the internal containeris sized and dimensioned to accommodate cell or tissue culturecontainers, and wherein the internal container has an opening throughwhich cell or tissue culture containers can be placed into or removedfrom the internal container. Most typically, a door is coupled to thehousing and/or the internal container and movable between an open(first) position that allows access to the internal container from theoutside of the incubator and a closed (second) second position thatprevents access to the internal container from the outside. Wheredesired, the housing and/or doors may also include EMI shielding toprevent interference of electromagnetic radiation with the incubator,associated equipment, and/or cells or tissues in the incubator.

As will be readily appreciated, the size, dimensions, and volume of theinternal container may vary considerably, and the particular use will atleast in part determine these dimensional parameters. Most typically,the internal container will be sized and dimensioned in accordance withcurrently known cell and tissue culture incubators. Thus, the volume ofthe internal container may vary depending on specific demands and willtypically be between 10-30 L, or between 30-50 L, or between 50-150 L,or between 100-200 L, or between 150-300 L, and even larger. Mosttypically, the incubators presented herein will be used as cell ortissue culture incubator, but in other embodiments, the devicespresented herein can also be configured as an incubator shaker,refrigerator, freezer, workbench, gloveless glovebox, etc. Thus,suitable volumes will be at least 10 L, or at least 20 L, or at least 50L, or at least 100 L, or at least 150 L, or at least 200 L, or evenmore.

A primary air flow control device is then coupled to the housing and/orthe internal container that directs a primary air veil along or parallelto a hypothetical plane covering the opening. In this context, it shouldbe noted that the phrase “along or parallel to a hypothetical planecovering the opening” is intended to express that the air veil willextend across substantially all of the opening (e.g., at least 85% or atleast 90% or at least 95% of the opening). Likewise, where the air veilis substantially parallel to the hypothetical plane, the angle betweenthe hypothetical plane and the air veil will be less than 30 degrees, orless than 20 degrees, and less than 15 degrees, or less than 10 degrees.Consequently, the air veil may be placed in front of the opening, behindthe opening, and/or within the opening. Moreover, it should berecognized that the air veil need not be a sheet-like structure havinguniform thickness but may also be configured as an air veil that has athinner portion on one end and a wide portion on the other end.Moreover, and as is described in more detail below, the air veil mayalso be a composite veil from multiple individual veil portions that actin concert as a single veil.

While not limiting to the inventive subject matter, it should beappreciated that the incubator may also comprise a secondary air flowcontrol device that is coupled to the housing and/or the internalcontainer and that directs a secondary air veil substantially parallelto the primary air veil. Once more, it should be noted that the phrase“secondary air veil substantially parallel to the primary air veil” isintended to express that the two air veils do not intersect, have adistance between them, and may be therefore be at an angle relative toeach other (less than 30 degrees, or less than 20 degrees, and less than15 degrees, or less than 10 degrees). Typically, the second air veilwill be of uniform thickness, but it is also contemplated that thesecond air veil may be thinner on one end and thicker on another end.

In still further contemplated aspects, it should be recognized that theprimary and secondary air veils are both preferably oriented in atop-down flow direction, or have a flow in the same direction (e.g.,both side-to-side). However, in less preferred aspects, the air veilsneed not be directed in the same orientation. Regardless of theorientation, it is typically preferred that the air veils are generatedby primary and/or secondary air flow control devices, and mostpreferably by tangential fans, air jets, and/or regular fans. As neededor desired, the airflow may be further directed through one or moredevices (e.g., honeycomb structure, cylindrical structures that may ormay not constrict, multiple blades or vanes, etc.) to assist innon-turbulent (directional or laminar) air flow. While not limiting tothe inventive subject matter, it is further contemplated that theprimary and/or secondary air flow control devices will be assisted byprimary and/or secondary suction fans to help stabilize the air veils.Accordingly, in preferred aspects of the inventive subject matter, theprimary suction fan will be positioned to receive air from the primaryair veil, and the secondary suction fan will be positioned to receiveair from the secondary air veil. In further preferred aspects, theprimary air veil and/or the secondary air veil may therefore bedirectional veils and/or a laminar flow veils. In yet furthercontemplated devices, the air veils may also be formed bycounterrotating fans producing a directional non-laminar flow.

As noted earlier, it is generally preferred that a substantial portionof the air in the primary air veil is recirculated through theincubator. While possible, such recirculation is typically notimplemented (or even necessary) for the secondary air veil. Accordingly,the air for the secondary air veil may be drawn from a location outsideof the incubator and may be vented via the secondary suction fan toanother location outside of the incubator. In at least that sense, firstand second air veils and primary and/or secondary air flow controldevices will/can be operated independently. In addition, it is generallycontemplated that at least the primary air flow control device willinclude a mechanism (e.g., a movable vane) that provides control overthe direction and/or geometry of the primary air veil. As will bediscussed in more detail below, such control is particularlyadvantageous where a portion of the primary air veil is directed intothe internal container to rapidly adjust one or more atmosphericparameters (e.g., temperature, gas concentration, humidity, etc.) in theinternal container.

Moreover, it should be appreciated that recirculation of the air fromthe primary air veil though a recirculation space will allow for rapidadjustment of one or more parameters of the recirculating air (e.g., gascomposition, temperature, humidity, etc.), and with that environmentalcontrol within the incubator. Most typically, the recirculation spacewill be formed by a space between the housing and the internal containerthat will most typically include several additional devices and/orsensors for control and/or adjustment of the one or more parameters ofthe recirculating air. For example, a filter unit (e.g., HEPA filter),an absorber unit (e.g. activated charcoal filter), a sterilization unit(e.g. UV based sterilization unit), a temperature control unit (e.g.heater), a temperature sensor, a humidity sensor, an atmosphericpressure sensor, and/or a gas sensor (e.g. O₂ and/or CO₂ sensor) may bedisposed within the recirculation space. Moreover, one or more gasinlets may be provided to the recirculation space through which gas(es)from an external source can be fed to the air in the recirculationspace. However, as shown in more detail below, the recirculation spacemay also be configured as a separate space/volume that is fluidlycoupled to the internal container.

In some embodiments contemplated incubators use distinct spaces (e.g.,an outer recirculation space and internal container) to separate the airvolume in the inner container from the air volume outside the innercontainer. In practice, it is not necessary for the recirculation spaceto wrap around the internal container as shown in the exemplaryincubator of FIGS. 6, 8, and 9. Indeed, it is contemplated that anyconfiguration which maintains the same primary and/or secondary air flowcontrol devices will work, including side-by-side, and piped designs.However, one significant benefit of the wrap-around design as shown isthat as the air volume circulates, the air will exhibit centrifugalbehavior, which will cause particles to preferentially stay near theoutside edges of the recirculation space, forcing them to pass throughand be caught by the filtration system built into recirculation space.In addition, any unmetered air entering the enclosure through theopening will also be caught and sent through the recirculation space tobe conditioned, allowing for lower environment transients in theinternal container. Another benefit of contemplated configurations isfor ease of maintenance (e.g. filter exchanges) during operation.

With respect to suitable doors it is contemplated that any door that canat least temporarily close the opening is deemed suitable for useherein, and contemplated doors can provide access to the internalcontainer by a rotating/pivoting motion (e.g., around a hinge), verticalor horizontal translating motion (e.g., using telescoping gear), or acompound motion (e.g., using trammel or compound pivot). However, it isgenerally preferred that the door is coupled to the housing and/or theinternal container in a manner such that the door moves the door (first)away and (then) in an upward motion from the opening. Such manner ofopening will advantageously reduce the severity of air motion forcingair from the inside of the incubator to the outside and/or the amount ofturbulent air between the door and the inside of the incubator chamber.For example, the door will preferably be movable in a non-pivotingmotion (not on a hinge or other pivoting mechanism extending along oneedge of the door), typically in a first movement along a Y-axis (towardsor away from the internal container) and a second movement parallel to ahypothetical plane extending across the opening (X- or Z-axis). Suchmovements are preferably sequential or may be performed in a singlecompound motion. Alternatively, the door may also be rotated about anaxis that is near, at, or outside the perimeter of the door (typicallyafter first moving the rotating door away from the opening). In furtherembodiments, the door may also be configured as a flexible or segmentedcover with each segment coupled to the next via a flexible connector orfilm (thus being similar to a segmented garage door). Such flexible orsegmented door can be moved in a sliding motion substantially parallelto the opening and towards a top or side wall of the internal containeror housing.

In addition, it should be noted that the door may also use a usemagnetic (or mechanic) door seal to accommodate pressure differencesbetween the inside and outside of the incubator. Where desired, it isfurther contemplated that the door may include a safety mechanism thatis designed to prevent closing onto a shelf or an operator, and suitablesafety mechanisms may be based on torque increase, optical sensors,and/or proximity sensors, all of which are well known in the art.Notably, it should be appreciated that contemplated incubators need nothave a door at all so that the so modified incubators can be used as aglove box, a (biosafety level 2+) cell or tissue culture bench, as afume hood, etc. Thus, it should be appreciated that the opening of theinternal container is shielded by dual air curtains/veils.Advantageously, such shielding significantly reduces, or even entirelyavoids contamination avoided due to a lack of contaminated air pushingor being sucked into the internal container as is common with heretoforeknown incubators. Viewed from a different perspective, the air veil(s)act as a virtual air-lock that prevents contamination while preservingthe environment of the internal container.

As will be readily appreciated, the operation of contemplated incubatorswill preferably be controlled via a pre-programmed and/or programmablecontrol circuit that will typically also be configured toinformationally communicate with various external devices (e.g., smartphones, tablets, network nodes or access points, etc.). In typicalaspects, the control circuit will electronically coupled at least to thedoor, the primary air flow control device, and/or the secondary air flowcontrol device, and most typically also to a temperature sensor, a gassensor (e.g., O₂ sensor or a CO₂ sensor), an atmospheric pressuresensor, and/or a humidity sensor, and wherein the control circuit isprogrammed to activate a heater, open a gas valve to allow entry of agas into the incubator, and/or activate a humidifier as is described inmore detail below. Still further, it should be appreciated that thecontrol circuit may be electronically coupled to an access controldevice that is programmed to receive a user command (e.g., voicecommand) and/or validate (e.g., via image recognition) an authorizeduser of the incubator, and that the control circuit will open and/orclose the door upon receiving the user command and/or validation of theauthorized user.

For example, suitable sensors include CO₂ and O₂ gas sensors (note thatthe N₂ concentration can be derived from sensed CO₂ and O₂concentrations), temperature sensors, humidity sensors, and air pressuresensors. In preferred embodiments, sensors for each environmentalparameter are present in triplicate to avoid “split-brain” sensingerrors, and the sensors can be placed in strategic locations in theairpath to allow faster response and more precise control. It shouldfurther be appreciated that sensors used in contemplated incubators canbe divided into nominal “fast” and “precision” categories. The fastsensors achieve reasonably accurate real-time results (generally under asecond), while precision sensors may take up to 15 seconds to settle butprovide a “calibration” level of accuracy. An example of fast sensorsare thermocouples which can be commonly sourced with typical accuraciesranging from 0.5 deg C. to 5 deg C. (depending on model) and with atypical response time within a tenth of a second. Examples of precisionsensors are Platinum RTD (Resistance Temperature Detector) sensors,which are generally available with accuracies from 0.1 deg C. to 1 degC. and with settling times ranging from 1 to 30 seconds.

In normal stable closed loop operation, the precision sensors are usedto maintain very precise control of the operating environment. Whenenvironment perturbations are detected (e.g., the door is opened), theincubator uses the fast sensors to rapidly access and correct for anydetected deviations. Once deviations settle, the incubator reverts backto the precise sensors for control. For example, temperature control canbe provided by a thermoelectric module located on the rear of therecirculation space that can provide heating (and moderate cooling, ifthe ambient is above 37 deg C.) capabilities. Oxygen/Nitrogen controlcan be provided by either a nitrogen tank as is well known in the artplus filtered compressed air or via a specialty mixed gas generator. CO₂is generally provided from a gas tank as is well known in the art. Forhumidity control, it is contemplated that the unit can use technologiesranging from the well-known traditional heated pan to dedicated humiditycontrol technologies such as molecular sieve adsorption for humidityreduction and external humidity generators for humidity increase.Optionally the unit can also control for precise air pressure, typicallyby feeding or bleeding gases into or from the incubator.

FIG. 2 depicts a side view of an exemplary configuration and airflow inan incubator with the closed door. In this exemplary view, it should berecognized that the door is in a closed position with only the primaryair control in operation (air flow is indicated by the arrows). As willbe appreciated, environmental control of the atmosphere in the internalcontainer of the incubator 200 is maintained by recirculation of airthrough the primary air flow control device 230 (with movable vanes 232)through the recirculation space 212 that is formed between the housing210 and the internal container 220. As can be seen from FIG. 2, therecirculation space includes an O₂ and a CO₂ sensor 270 and 272, aheater 280, gas inlets 282, filters 283 (activated charcoal), 284(HEPA), and a sterilization unit 290. The air veil is formed between theprimary air flow control device and the primary suction fan 240, and theair veil geometry and direction is controlled by the movable vanes 232.In this exemplary configuration, where the door is in a closed position,the air veil may be throttled down (e.g., between 50-90% of air volumeflow, or between 20-50% of air volume flow, or between 20-50% of airvolume flow) relative to a time where the door is opened, and the airvail my only temporarily operate where desired. The secondary air flowcontrol device 250 and secondary suction fan 260 are turned off in thisexample. Moreover, it should be noted that the vanes may be moved suchthat at least some portion of the air of the air veil will be directedinto the internal container before recirculation via the primary suctionfan. Depending on the particular set points for the atmosphericparameters, it should be noted that the sensors will provide signals tothe control unit (not shown) to so activate the heater, the gasinlet(s), and other devices to maintain the atmospheric parameters atthe desired levels. Here, it should be especially recognized that allmeasurements can be performed in real time, that all correctiveactivities can be implemented in real time, and that the recirculationof the air through the veil and recirculation space will allow for rapidequilibration of the atmospheric parameters.

For example, recirculation rates may be adjusted such that between 0.01and 0.1, or between 0.1 and 1.0, or between 1.0-3.0, or between 3.0-5.0,or between 5.0 and 10.0 (and even higher) internal volumes arerecirculated within a time period of between 10 sec and 60 sec, orbetween 1 min and 5 min, or between 5 min and 15 min, or between 15 minand 1 hour. Of course, it should be recognized that these recirculationrates may vary due to specific operating conditions. For example, higherrates are typically needed where the doors are frequently opened andclosed, where an operator frequently accesses the internal container,where gas concentrations need to change from one to another set point,etc. Conversely, where the doors remain closed over extended periods,the recirculation rates may be lower. Thus, the primary air flow controldevice may deliver an air flow of between 0.1-1 liter/min, or between1-10 liter/min, or between 10-100 liter/min, or between 100-500liter/min (STP). Of course, in this context it should be recognized thatthe recirculation volume will not only depend on the operatingconditions, but also on the volume of the internal container. However,in many embodiments the volume of the internal container will be between10-100, or between 100-200 liter, or between 200-400 liter, or between400-1,000 liter, or between 1,000-5,000 liter, and in some cases evenhigher.

Upon opening the door (e.g., in a compound motion as noted above), asecondary air veil may be established as is shown in FIG. 3. Here, theairflow is shown once more with arrows, and the secondary air veil isgenerated via the secondary air flow control device and the secondarysuction fan. Of note, it should be appreciated that in this example thesecond air veil is not or substantially not (i.e., less than 10% of theair in the secondary air veil) recirculated, but vented to the outsideof the incubator. While not wishing to be bound by any theory orhypothesis, it is contemplated that a secondary air veil will protectthe primary air veil and establishes a first barrier againstenvironmental disruption while the door is opening and/or opened.Moreover, where a user penetrates both air veils with his/her hands andarms, the primary and secondary air veils will cooperate to minimizeenvironmental disruption within the interior container of the incubator.As will further be appreciated, any potential airborne contaminant willprimarily enter the recirculation air stream first and be eliminated inthe filters and sterilization unit. As such, the air veils will not onlyreduce environmental disruption but also maintain sterile operation.FIG. 4 depicts another exemplary view of airflow in an incubator withthe door fully open. As is exemplarily shown, filtration andsterilization of the recirculating air is readily achieved while at thesame time the primary and secondary airs help maintain the atmosphericparameters set within the internal container.

In yet a further advantageous use of the incubator components presentedherein, it should be noted that any disruption in the atmosphericparameters can be corrected in real time while maintaining the primaryand/or secondary air veils as is exemplarily shown in FIG. 5. Here, thevanes of the primary air flow control device are controlled to direct atleast a portion of the air flow from the primary veil into the internalcontainer before re-entering the recirculation space. Such redirectionis particularly advantageous as disruptions in the atmosphericparameters measured by the sensors in the recirculation space can becorrected in real time while the door is open, and the corrections(e.g., added heat, humidity, N₂, and/or CO₂) can be implemented in realtime.

With regard to the volumetric air flow in the primary and secondary airveil it should be noted that these air flows can be adjusted as neededin a flexible or pre-programmed manner. For example, where one or moresensors detect a user's hand or arm passing through the primary and/orsecondary veil, the air flow can be decreased in the primary and/orsecondary air veil to reduce turbulent air flow. On the other hand,where the door is opening, the air flow can be increased in the primaryand/or secondary air veil in a pre-programmed manner. Alternatively oradditionally, air flow rates may be modulated in a more fine-grainedmanner where multiple air flow control devices are implemented toproduce a single air veil (e.g., reduce flow where hand or arm isdetected, increase flow in others). Thus, multiple air flow controldevices can be employed to generate an air veil ‘around’ an obstruction.In view of the above, it should therefore be appreciated that incubatorsaccording to the inventive subject matter will substantially reduce, oreven eliminate variability or excursions in atmospheric parametersinside the incubator regardless of the conditions outside the incubatorand even during times where a user accesses the internal container.

Depending on the particular size and configuration of the incubator, theair flow in the primary air veil and/or secondary air veil may thereforebe at least 0.1 L/min, or at least 0.2 L/min, or at least 0.5 L/min, orat least 1.0 L/min, or at least 2.0 L/min, or at least 5.0 L/min, or atleast 010 L/min, or at least 20 L/min, or at least 50 L/min, or at least100 L/min. For example, typical air flow in the primary air veil and/orsecondary air veil may be between 0.1 L/min and 1.0 L/min, or between1.0 L/min and 5.0 L/min, or between 5.0 L/min and 10 L/min, or between10 L/min and 50 L/min, or between 50 L/min and 100 L/min, or evenhigher.

FIG. 6 provides another exemplary perspective view of an incubator ascontemplated herein with primary and secondary primary air flow controldevices and corresponding primary and secondary suction fans. Regardingsuitable air flow, FIG. 7 exemplarily depicts a graph in which air flowbehavior is shown as a function of the height of the air veil and exitvelocity of air from the air flow control devices. As can be readilyseen laminar flow can be achieved over a large distance at relativemoderate exit velocity. Moreover, it should be noted that there is asignificant transition region in which air flow is not linear but alsonot fully turbulent (transition region). Such transitional flow is alsodeemed suitable for use herein as the air flow can still be directionalover a long distance. Indeed, ordered or semi-ordered air flow onlybreaks down at relatively long distances.

To establish a desirable air flow, the path for the internal containerand the recirculation space was designed using extensive computationalfluid dynamics modeling in addition to empirical testing. While theconcept of an air veil works with any method which can maintaindirectional flow, it is typically preferred to generate a laminar flowas much as possible for the highest efficiency in environmentalcontainment. To that end, the air veils were generated by two separateair flow control device that worked in tandem to create a guide layerwhich preserved the airflow boundary that separates the outside air fromthe conditioned air inside the incubator. Notably, using differentialair velocities from the air flow control devices enabled steering of theairflow boundary to split the edge of the opening. In one exemplaryconfiguration (as shown in FIG. 6, door in open position not shown), alloutside air was forced through the recirculation space first forfiltration, sanitation, and compensation. In this example, the outside(secondary) air veil had two sets of fans. The top fan employedprefiltering of ambient air with a HEPA filter and used shaped outletducts to help create a laminar sheet of air. The bottom (suction) fanwas used to shape the airpath of the laminar flow and exhaust thecollected air into the room. Thus, the secondary air veil was notsubject to recirculation.

The inside (primary) air veil drew air from the recirculation space andexhausted it through shaped ducts, again forming a laminar sheet of airacross the opening, bounded on one side by the laminar sheet generatedby the outside air veil and by the internal container on the other side.At the end of the airpath is an opening which leads back into therecirculation space with its associated filtering and conditioningtechnologies via a bottom (suction) fan. It should be appreciated,however, that it is not strictly necessary to implement an external airveil, but its lack would likely result in more air exchange (due to aless than ideal airflow profile) that could be compensated for.

In the computational fluid dynamics modeling simulations (with inputsbased on empirical measurements) multiple design iterations were made toexamine the desirable flow characteristics. In the example of FIG. 6,the inventors determined that a desirable airflow of the air veil was inthe region of 0.3 meters per second up to 0.6 meters per second, leadingto laminar flow or near-laminar flow. Faster air velocities were moreprone to turbulent transitional regions (which decrease overallcontainment efficiency by causing more mixing in the air boundary), andslower air velocities were more likely subject to the effect of externalinterference such as fast moving air currents (e.g. a room fan or peoplewalking by) in the proximity of the air veils. Nevertheless, alternativeairflow of the air veil may also be in the region of 0.05-0.1, or0.1-0.2, or 0.2-0.3 meters per second or in the region of 0.6-0.7, or0.7-0.8, or 0.8-0.9, or 0.9-1.0 meters per second, and even higher.

It should further be appreciated that the air flow in the primary airveil may be variable and regulated upon demand by specific operatingmodes. For example, where the door is closed, air flow may be lower thanwhen the door is open. On the other hand, where new operating conditionsare set, air flow may be increased relative to steady-state operation.Likewise, the air flow in the secondary air veil may be variable andadjusted to specific circumstances. For example, when the door isclosed, no air flow may be present. Upon opening the door, airflow maybe increased to the same or similar air flow as the primary air veil. Onthe other hand, where a hand or arm of an individual entering theopening is detected air flow in the secondary air veil may be increasedto a flow rate above that of the primary air veil.

In further aspects during normal operation, contemplated incubators mayminimize air currents in the internal container (similar to the eye of ahurricane). However, it should be recognized that there are occasionswhen rapid air exchange is desired, for example when the incubator isstarted for the first time. In such cases, the air current can besteered or shaped inside the internal container, either by usingdifferential air velocities between the two veil units or by simplyusing vanes/nozzles to vector the air directly into the internalcontainer.

It should also be appreciated that due to the airpath of the dualchamber design (recirculation space and internal container),fluctuations in the environmental parameters are kept in therecirculation space and be corrected before diffusing into the calmerinternal container. FIG. 8 and FIG. 9 depict exemplary results from thecomputational fluid dynamics modeling with different air flowvelocities, where the air flow in FIG. 8 was less than the air flow inFIG. 9. FIG. 10 depicts an alternate configuration in which therecirculation space is separate from the internal container, and inwhich adjustments in one or more environmental parameters are madewithin the separate external chamber that is fluidly coupled to theinternal container by an entry and exit duct.

FIG. 11 depicts a perspective view of an incubator according to theinventive subject matter with a screen and camera above the screen. Inthis example, the screen is preferably a touch sensitive screen that canaccept user input, for example, to set atmospheric parameters in theincubator and/or to enter a password where access is restricted.Moreover, the screen will also typically provide further user controls(e.g., to override a programmed mode, or to modify one or moreparameters) and operational status, etc. With respect to the videocamera it is contemplated that the camera can use image recognition tonot only authenticate specific (e.g., pre-approved) users but also torecognize gestures that correspond to specific operational controls. Ofcourse, it should also be noted that access control may include use of amicrophone and audio processing software to enable voice commands, whichmay be matched with image recognition. FIG. 12 shows the incubator ofFIG. 11 in an open configuration, and FIG. 13 is a detail view of theincubator of FIG. 12 showing the air intake sections for the primary andsecondary suction fans. FIG. 14 is another detail view of the incubatorof FIG. 12 showing the open door and primary and secondary air flowcontrol devices, along with the movable vanes. Finally, FIG. 15 depictsa perspective view of an exemplary incubator.

For example, suitable user interfaces may be part of the control unit orseparate and be electronically coupled with the user interface. Amongother options, contemplated user interface features include a frontfacing camera for facial detection and access logging. 3D scanningtechnology (e.g., Intel Realsense 3D) for gesture recognition forcontactless control of incubator functions, and/or voice detection forsimple control. In further embodiments, the incubator will have a largefront panel display for fast status check and easier navigation ofoptions. Built-in networking units may be provided so incubators can bemonitored from a PC or tablet, and alerts can be set to notify a user incase of operational or other technical issues. Where desired, cloudaccess may be enabled to store and/or pull known ideal/workingenvironmental conditions for various cell lines as well as facilitateresearcher collaboration.

Therefore, in some preferred aspects, contemplated incubators will havea housing that at least partially encloses an internal container,wherein the internal container has an opening. A primary air flowcontrol device is coupled to the housing and/or the internal containerand directs a primary air veil along or substantially parallel to ahypothetical plane covering the opening, wherein the housing, theinternal container, and the primary air flow control device arepositioned relative to each other to form a recirculation space thatallows for recirculation of air in the primary air veil. As noted above,the recirculation space at least partially encloses a plurality ofsensors (e.g., CO₂ sensor, O₂ sensor, humidity sensor, atmosphericpressure sensor, and/or temperature sensor), and further at leastpartially encloses a sterilization unit, a high-efficiency particulateair (HEPA) filter, an activated charcoal filter, and/or a heater.Moreover, it is typically preferred that the recirculation space alsoincludes one or more parts through which one or more gases (e.g.,ambient air, N₂, CO₂, etc.) can be delivered to the recirculation space.

Regardless of the particular configuration, contemplated incubators willalso include (or are informationally/electronically coupled to anincubator control unit that has a microprocessor and a memory storinginstructions executable on the microprocessor, where the instructionscause the control unit to down-regulate the primary air flow controldevice and optionally cause movement of a vane coupled to the primaryair flow control device upon the door moving into the second position,up-regulate the primary air flow control device and an optionalsecondary air flow control device upon the door moving into the firstposition, and/or cause movement of a vane coupled to the primary airflow control device when the door is in the first position.

Of course, the control unit will preferably also be electronicallycoupled to various sensors and effector circuits to maintain, regulate,and/or adjust one or more atmospheric parameters within the incubator.For example, the control unit may be electronically coupled to atemperature sensor, a gas sensor (e.g., O₂ sensor or a CO₂ sensor), anatmospheric pressure sensor, and/or a humidity sensor, and theinstructions may cause the control unit to activate a heater, open a gasvalve to allow entry of a gas into the incubator, and/or activate ahumidifier. As will be readily appreciated, multiple redundant sensorsof the same type (e.g., 3 or more) may be used to ensure continuousoperation even when a single sensor fails. For example, the instructionsmay cause the control unit to activate the heater, to open the gas valveto allow entry of the gas into the incubator, and/or activate thehumidifier when the door is being opened or is in an open position.Where desired, and as already noted above, the control unit may also beelectronically coupled to an access control device that is programmed toreceive a user command and/or validate an authorized user of theincubator, and wherein the instructions cause the control unit to openor close the door upon receiving the user command and/or validation ofthe authorized user. As will be readily appreciated, one or morefunctions of the control unit (e.g., door opening and closing,adjustment of operational parameters, gas flow, operation of air flowcontrol device, and/or vane position) may also be effected by a manual,mechanical or analog control device to so provide redundancy to thesystem in case of a power failure or other operational downturn.

In additional aspects of the inventive subject matter, contemplatedincubators may also include an atmospheric pressure sensor and/or analtimeter to allow for correct partial pressures of gases irrespectiveof the particular geographic location of the incubator. Moreover, eventhough under most circumstances contemplated incubators will operate atambient pressure levels, it is contemplated that the incubatorscontemplated herein may include a pressure control unit to allow foroperation at increased pressure. Where desired, suitable incubators mayfurther include ancillary functionalities such as a red light source,one or more electronic outlets and connections, one or more wirelessinterfaces (e.g., to gather/transmit operational data and/or status,change operational parameters, etc.).

To further reduce excursion of atmospheric parameters within theincubator, it is also contemplated that shelfs or other moving parts maybe configured to minimize the air veil. For example, a tray may beconfigured to include channels extending therethrough that allow flow ofthe air veil without generation of (or with significantly reduced)turbulent air flow. Among other options, a tray may be configured tohave a honeycomb structure that permits airflow across the tray. Tofurther facilitate servicing of and/or access to the various components,it is typically preferred that the internal container may be slidingly(e.g., via a rail or telescoping mechanism) coupled to the housing suchthat the housing remains stationary and that the internal container ismoved away from the housing.

In still further contemplated aspects, it should be appreciated that theprimary and/or secondary air veils may not only be suitable for use withan incubator as presented herein, but that the air veils may also beimplemented in a glove box. Consequently, it should be noted that aglove box need no longer have a mechanically sealed environment withglove ports, but that at least a portion of the front enclosure facingan operator may be completely open but be protected by the primaryand/or secondary air veils.

While contemplated incubators can be operated as most conventionalincubators using one or more defined gases (such as N₂ and/or CO₂) it isfurther contemplated that the gases may also be provided by a separategas supply system. Most preferably, contemplated gas supply systems willinclude an ambient air compressor to produce a compressed gas supply. Aswill be readily appreciated, the compressed ambient air will typicallybe subjected to cooling, dehumidification (e.g., via deep cooling,molecular sieves, adsorbents, etc.), and de-oiling where needed. Oncecompressed, at least a portion of the compressed ambient air is thensubject to a step of air separation, preferably using anitrogen-permissive membrane and/or pressure swing adsorption (PSA) unitto produce a product stream that is enriched in N₂ (typically at least80%, or at least 85%, or at least 90%, or at least 95%, or at least 98%N₂). This N₂ enriched product stream is preferably stored in a nitrogenbuffer tank from which a portion can be fed to a mixing unit. At leastanother portion of the compressed ambient air (containing about 21% O₂)can be fed to the mixing unit. Where desired, a source of CO₂ (e.g.,having a purity at least 80%, or at least 85%, or at least 90%, or atleast 95%, or at least 98% CO₂) may be fluidly coupled to the mixingunit. In most embodiments, the mixing unit will be configured as amanifold that can receive the compressed air, the N₂ enriched productstream, and the CO₂ product, and that has an outlet for a mixture of thecompressed air, the N₂ enriched product stream, and the CO₂ product.While not needed, a dynamic or static mixer may assist in gas mixing.

As will be readily appreciated, each of the conduits delivering thecompressed air, the N₂ enriched product stream, and the CO₂ product willtypically include an electronic flow valve and a mass flow meter toascertain precise control over the amount of gas that is to be deliveredto the mixing unit. Moreover, it is also typically preferred that theconduit for the mixture leaving the mixing unit will also include one ormore gas sensors (e.g., O₂ and a CO₂ sensor) that provide signals to acontrol unit (which may be the incubator control unit or an externalcontrol unit) to accurately control the gas composition to apredetermined set point or band. Typically, but not necessarily, themixture leaving the mixing unit may be fed to a surge or storage tankthat then delivers the gas mixture to an incubator, and an exemplary gassupply system is depicted in FIG. 16. Where multiple incubators are usedwith respective distinct gas compositions, each incubator may be fedfrom a separate surge or storage tank, all of which may be fed from thesame gas supply system as is exemplarily shown in FIG. 17.

In still further contemplated aspects of the inventive subject matter itshould be recognized that the incubators presented herein mayadvantageously use gas sources that provide raw gases or gases with lessthan 99-100% purity, and/or gases with less (or not exactly) definedcompositions. Moreover, contemplated incubators may even receive gaseswith changing composition. Such is particularly beneficial as mosttypical incubators require the use of certified gases with knowncomposition, which are notoriously expensive. For example, mostincubators require pure nitrogen and/or pure CO₂, or a premixed ‘trigas’supply. By placement of a set of gas sensors at the gas inlets andmeasuring the real-time supplied gas concentrations, valving can now beadjusted in real time as needed to maintain a desired gas mix. In thiscontext it should be noted that most tissue culture experiments areperformed with gas concentrations at −5%-6% CO₂ (as a buffering agent),<0.5-20.95% O₂, at sea level, with the balance being N₂. It is thereforeevident that certified high-purity (e.g., 100% concentration) gases arenot absolutely required and that one can use, for example, 99.5%nitrogen or even a 95% nitrogen source (this number may vary dependingcell type requirements). Consequently, the raw output of a single stageof a nitrogen generator can be used with or without a buffer tank. Instill further examples, it should also be noted that the incubatorspresented herein can be operated as commonly known CO₂ incubators (andas such may not necessarily require oxygen sensors). Thus, it should berecognized that the devices and methods allow for a wide operationalflexibility for use.

In still further contemplated aspects, contemplated gas supply systemswill also make use of a look-up table providing correction factors fornon-ideal gases such as CO₂, which may significantly deviate from gasbehavior of N₂ and O₂ (e.g., with respect to compressibility). Thesecorrection factors can then be employed in equations to controlappropriate CO₂ supply.

In yet further contemplated aspects, it should be appreciated thatincubators as presented herein may also be set up from conventionalincubators using a retrofit kit. Most typically, the incubator door of aconventional incubator in such scenario is replaced by a retrofit kitthat includes a mounting frame coupled to a primary air flow controldevice and a primary suction fan (and optionally a secondary air flowdevice and secondary suction fan), wherein the recirculation is formedbetween the primary air flow device and primary suction fan by anexternal recirculation volume, for example, via suitable ducting and anoptional a surge vessel. The external recirculation volume willpreferably include one or more functional elements such as sensors, gasinlets, filters, etc. as described above. Finally it should beappreciated that while use of contemplated devices and methods will beespecially suitable for cell and tissue culture, contemplated devicesand methods are also suitable for environments where the temperature isat or below 20° C., at or below 10° C., at or below 4° C., at or below0° C., at or below −10° C., at or below −20° C., at or below −40° C., oreven lower.

Lastly, it should noted that the operational assembly (i.e., theinternal container and the recirculation space) may be configured toallow removal in a single unit (e.g., assembly can be pulled out) foreasy maintenance of replacement of consumables such as filters.

The recitation of ranges of values herein is merely intended to serve asa shorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided with respectto certain embodiments herein is intended merely to better illuminatethe full scope of the present disclosure, and does not pose a limitationon the scope of the invention otherwise claimed. No language in thespecification should be construed as indicating any non-claimed elementessential to the practice of the claimed invention.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the full scope of the concepts disclosed herein. Thedisclosed subject matter, therefore, is not to be restricted except inthe scope of the appended claims. Moreover, in interpreting both thespecification and the claims, all terms should be interpreted in thebroadest possible manner consistent with the context. In particular, theterms “comprises” and “comprising” should be interpreted as referring toelements, components, or steps in a non-exclusive manner, indicatingthat the referenced elements, components, or steps may be present, orutilized, or combined with other elements, components, or steps that arenot expressly referenced. Where the specification claims refers to atleast one of something selected from the group consisting of A, B, C . .. and N, the text should be interpreted as requiring only one elementfrom the group, not A plus N, or B plus N, etc.

What is claimed is:
 1. A controlled atmosphere device, comprising: ahousing that at least partially encloses an internal container, whereinthe internal container has an opening; primary and secondary air flowcontrol devices coupled to the device that are configured to generaterespective primary and secondary air veils flowing substantiallyparallel to each other and along or substantially parallel to ahypothetical plane covering the opening; wherein the primary air flowcontrol device comprises a vane that is configured to allow changingdirection of the primary air veil during at least some time of operationto thereby enable mixing of air in the internal container of the device;and wherein the device is configured as a glove box, a cell or tissueculture bench, or a fume hood; or wherein the device is configured as acell or tissue culture incubator that further comprises a door that iscoupled to the housing and/or the internal container such that the dooris movable in a non-pivoting motion.
 2. The device of claim 1, furthercomprising an EMI shielding coupled to the housing.
 3. The device ofclaim 1, further comprising a light source coupled to the container. 4.The device of claim 1, further comprising one or more wirelessinterfaces configured to transmit operational data, transmit statusdata, and/or to change operational parameters of the device.
 5. Thedevice of claim 1, further comprising a pressure control unit configuredto allow for operation of the device at increased pressure.
 6. Thedevice of claim 1, further comprising an atmospheric pressure sensorand/or an altimeter configured to allow for correction of partialpressures of gases irrespective of the particular geographic location ofthe device.
 7. The device of claim 1, further comprising a front facingcamera configured to allow facial detection and/or gesture recognition.8. The device of claim 1, wherein the internal container has a volume ofbetween 100-300 L.
 9. The device of claim 1, wherein a space between theinternal container and the housing forms a recirculation space that isconfigured to induce centrifugal flow of air moving in the recirculationspace.
 10. The device of claim 1, wherein the door is configured as aflexible or segmented cover to enable a sliding motion substantiallyparallel to the opening and towards a top or side wall of the internalcontainer or housing.
 11. The device of claim 1, wherein the door iscoupled to a safety mechanism that prevents closing of the door onto ashelf or an operator.
 12. The device of claim 11, wherein the safetymechanism is triggered by torque increase, an optical sensor, and/or aproximity sensor.
 13. The device of claim 1, further comprising a traythat is configured to minimize disturbance in the primary and/orsecondary air veils.
 14. The device of claim 13, wherein the traycomprises a structure that permits airflow across the tray.
 15. Thedevice of claim 1, wherein the internal container is slidingly coupledto the housing such that the housing remains stationary and such thatthe internal container can be moved away from the housing.
 16. Thedevice of claim 1, wherein the device is coupled to a gas supply. 17.The device of claim 16, wherein the gas supply comprises a nitrogengenerator, a carbon dioxide tank, and a gas compressor.
 18. The deviceof claim 17, wherein the nitrogen generator comprises a pressure swingadsorption unit or a membrane filtration unit.
 19. The device of claim1, wherein the device is configured as the glove box, the cell or tissueculture bench, or the fume hood.
 20. The device of claim 1, wherein thedevice is configured as the cell or tissue culture incubator.